Remote control system for radio receivers



April 20, 1937. L. M. CLEMENT 2,078,060

REMOTE CONTROL SYSTEM FOR RADIO RECEIVERS Filed Oct. 16, 1929 4 Sheets-Sheet 1 INVENTOR LEW/S BY CLEMEZYT.

ATTORNEY April 20, 1937. M. CLEMENT- REMOTE CONTROL SYSTEM FOR RADIO RECEIVERS Filed Oct..' 16, 1929 4 Sheet-Sheet 2 'INVENTOR LEW/5 M. CLEMENI @ZZ/ZW ATTORNEY April 9 M. CLEMENT REMOTE CONTROL SYSTEM FOR RADIO RECEIVERS 4 Sheet-Sheet 3 Filed Oct. 16, I929 INVENTOR LEW/8 M. CLEMENT.

ATTORNEY April 20, 1937. L. M. CLEMENT I .0

REMOTE CONTROL SYSTEM FOR RADIO RECEIVERS Filed'bqt. 16, 1929 4 Sheets-Sheet 4 INVENTOR LEW/S M. CLEMEHI' BY A, a =MKMM ATTORNEY Patented Apr. 20, 1937 UNITED STATES PATENT OFFlCE RWOTE CONTROL SYSTEM For; mmro signor, by mesne assignments, to Federal Telegraph Company, Newark, N. J., a corporation of California Application October 16, 1929, Serial No. 399,892.

2 Claim.

This invention relates to high frequency receiving systems, and particularly to a method of and means for controlling such systems from a.

point or points remote therefrom.

An object of the invention is to control high frequency receiving systems from a remote control point.

Another object of the invention is to tune a high frequency receiving system from a point remote from the receiver.

A further object of the invention is to tune a radio receiver to predetermined carrier frequencies by making selected circuit contacts at Points remote from the receiver.

A still further object of the invention is to, control a receiver from a remote point or at the receiver and indicate at the remote point and at the receiver the energization thereof and the period during which the receiver is being tuned.

This invention contemplates the use of a high frequency receiver located at a particular point, the tuning thereof to be accomplished from a number of-points located at various positions remote therefrom. The receiver, for instance, which may be of the console type with the loud speaker mounted in the cabinet, may be located in one room with the remote control unit placed on the arm of a chair, on a table or in other rooms. tuning unit and amplifier located in the cellar,

attic or any portion of the house, with the control unit placed in any convenient location. The loud speaker, of course, will be in the place of reception.

The embodiment of the remote control system disclosed herein employs a plurality of buttons for selecting desired stations, the tuning being accomplished by merely pressing the button for any particular station. Intermediate stations 40 may be also tuned in by manipulating the tuning buttons on the extreme ends of the control unit when the holding relays are made inoperative. Tuning at the receiver itself may be accomplished by preselecting buttons or a manual dial control, as is well known in the art.

The present system employs a motor with two field windings, the energization of one of which causes the motor to rotate in one direction, and the energization of the other causes the motor to rotate in the opposite direction/Volume con-- trol is provided from both the remote points and at the receiver by means of potentiometers which vary the potentials on the screen grid tubes employed in the receiver. Indicating lights show- The receiver may also comprise only a ing when the set is energized and lights showing the period of tuning are also provided.

Relays control the starting and stopping and the changing of the volume control from one unit to another. The rotating mechanism is stopped at a particular station by means of a clutch which disconnects the motor at the desired resonant point of the tuning element. A commutator' ring of two segments insulated from one another, provides the circuit breaking mechanism at the preselected position.

The entire system is operable from an A. C. source, no batteries of any kind being required.

The invention will be more fully understood by reference to the accompanying drawings, in which:

Figure 1 is a schematic drawing of the system embodying applicant's invention;

Figure 2 is a perspective view of the motor and selecting plate of the remote control mechanism of the unit located at the receiver;

Figure 3 is a front view of the escutcheon plate of the unit located at the receiver;

Figure 4 is a perspective view of a remote control unit;

Figure 5 is a perspective view of an adjustable preselecting button;

Figure 6 is a single line diagram of the invention; and

Figure 7 is a detailed view showing the split ring means for locating the broadcast frequencies.

In the following description identical numbers will indicate similar elements in all the drawings.

Referring to the circuit diagram in Figure 1 and the block diagram in Figure 6, a receiver of any well-known type, preferably employing screen grid tubes, is shown as unit A, an amplifler containing two stages of push-pull amplification is shown as unit B, and a power supply unit containing a full wave rectifier is shown as unit C. An electro-dynamic loud speaker D is shown with its electro-magnet coil 5 and voice coil 0. Power is supplied to the-system through a plug 8, which may be attached-tp the house lighting-circuit, and an interconnectihg plug Q. Signals are received over an aerial ill. The remote control system is shown in the upper portion of the drawing of Figure l, the remote unit eing shown at E, and the units F and G thereof being located in the receiver cabinet.

The unit A contains three stages of radio frequency amplification and a detector, the radio frequency stages employing screen grid tubes M, iii, and it. The volume is controlled by varying the potential on the screen grids over conductors I5.

The unit B contains two stages I6 and I1 of push-pull amplification with a preliminary single stage of audio-frequency amplification I6, these stages being transformer coupled; Power for the radio receiver is supplied through power transformer 26 in unit C, the alternating current being rectified by a full wave rectifier 2i having the usual filter circuit 22. The filaments are all heated with alternating current either indirectly as in the heater type of tubes, or directly as in the last stage of push-pull amplification, from the power transformer 26.

The unit F contains push-button switches 25 'with magnetic hold-down relays 26, together with a split ring commutator 21 adapted to rotate with the tuning condenser shaft and associate contact buttons 26. This unit also contains a motor 36 with its two field windings 3| and 32. A coil 34 shown in this unit is the magnetic brake coil which disconnects the motor from the tuning mechanism as will be explained hereinafter. 'A resistance 33 is employed to reduce the voltage for the motor 36.

The unit F also shows an energization indicating lamp 36, tuning control lamp 31, start and stop buttons 46 and 4|, together with a volume control I42. Another portion of unit F is a phonograph throwover switch 44 located under the volume control button 42 as shown in Figure 3.

A phonograph pick-up may be connected to the terminals 45 and connected through the switch over conductors 46, contacts 41 and conductors 46.

The unit G or relay panel includes the start relay 56, stop relay 5|, volume control relay 62 for the remote point, and volume control relay 53 for the cabinet, together with a relay 54 for short circuiting the loud speaker during the timing operation.

The remote control unit'shown in E comprises remote control tuning buttons 56, tuning light 51, volume control 56, energization indicating light 59, start button 66, and stop button 6I, the connecting cables conductors.

In Figures 2 and '7- the mechanism of the control unit located at the cabinet is shown in detail. A universal joint 66 is shown for coupling the condenser shaft to the motor which drives the shaft through gears 66 and 61. The gear 61 drives shaft 66 through pins 69, which are inserted in the holes of the gear 61. The shaft 66 is connected by flexible cord" to the condenser shaft driving means. The gear 61 may be re-- moved from the pins by the action of a spring 16 acting through an armature lever 1| mounted on the pivot 12. In normal condition this gear is removed from the driving pins 69 and is connected thereto only when the coil 34 is energized. The shaft 66 has mounted thereon a control knob 15 for manual control at the receiver. Manual control may be had at any time the receiver is not being tuned as the shaft 66 is normally free of the gear 61.

The ring 21 is shown in Figures2 and '7 in two portions, insulated from one another byinsulation 16.. The ring portions revolve until one of the contacts 11 on the adjusting devices 26 conindicated as 63 containing I5- The devices 26 are mounted on portions of the escutcheon plate 66 and are numbered to correspond with buttons 25 at the cabinet and buttons 56 at the remote unit respectively. These devices are held in position by hand screws 23.

Adjustment is made by tuning the receiver to the desired station by knob 15 and then placing the contact 11 on theinsulator 16 and fastening the device at this position. A dial 6| is shown for indicating the position of the tuning condensers, the dial being transparent and illuminated by a lamp 62. A terminal plate 36 is provided on this unit tomake the connections of the conductors leading thereto. In Figure '7, binding posts 49 are mounted on the split, ring 21 and are connected to flexible leads. These leads connect with the motor field coils 3| and 32.

Referring particularly to Figure 1 again, and

' to the other figures, to show the elements affected, the circuit operates in the following manner:

When the start button 46 is pressed, it completes a circuit through relay 66 over conductor 96, switch 46, conductor 9|, relay 53, conductor 92 and through the secondary winding of transformer 93. Actuation of the relay 66 trips the armature of relay 5i, closing contacts 94 and 96. The energization of relay 63 closes contacts 96 and 91 on its armature. The closing of contact 95 completes a circuit from the power plug 6 through contact 95, conductor 96, plug 9, primary of power transformer 26, and back through plug 9 and conductor 99. This circuit energizes the radio receiver. The closing of contact 94 completes a circuit from a tapped portion of the secondary of transformer 93 through contact 94, conductor I23, lamp 69 and conductor I24 to one terminal of the secondary winding of transformer 93, thereby showing at the remote point that the receiver is energized. Lamp 36 at the receiver is energized from transformer 26 over conductors I26 to show that the system is ready for operation. The closing of contacts 96 and 91 connects the volume control potentiometer 42 at the receiver to the control grids of the receiver over conductors I6, permitting the volume of the receiver to be controlled at the cabinet.

The receiver may now be tuned through any of the button switches 26 at the local point, and also through the button switches 56 at the remote point, the volume control, however, being at the local point.

The closing of any switches of the buttons 26 for instance switch I66 completes the following circuit: From switch I66, through conductor III, holding coil I62, contact I63 of the adjustment devices 26, split ring 21, conductor I64, field winding 32, motor 36, lamp 31 with its protective resistance I 65, conductor I66, relay 54, conductor I61. secondary winding of transformer 93, conductor 92. conductor I 66, resistance 33 to switch I 66. When this circuit is made coil I62 is energized. closing its contact I69, which maintains the circuit after switch I66 is opened by the release of pressure on it until the ring 21 has been rotated so that its insulation 16 reaches contact I63. breaking the circuit. During the completion of this circuit relay 64is energized, making contacts H2 and H3. The closing of contact II2 short-circuits the voice coil 6 of the speaker D over conductors H4. The closing of contact 3 actuates the coil 34, which is energized over conductor II6,.conductor II1, rectifier 2I and one of the conductors H4. The completion-of the motor circuit also ene izes lamp 31 which indicates that the receiver s in the process of being tuned.

,To dc-energize the receiver, pressure on the button 4I energizes the relay 5I over conductor I20, switch 4|, conductor 9|, relay 53, and conductor 92 from the secondary of transformer 93. Operation of the relay 5I breaks contacts 94 and 95, breaking the receiver energizing circuit. Lamps 59 and 36 are thereby extinguished in directing the de-energization of the system.

' To start the receiver from the remote point,

pressure .on button 50 energizes relay 50 over conductor I2I switch 50, conductor I22, relay 52 and conductor 92 from the secondary winding of Operation of relay 50 closes lighting the signal lamp 59 over conductor I23 and conductor I24 and lighting lamp 36 over conductors I26. Energization of the relay 52 trips the armature of relay 53 and closes contacts I21 and I28, which connects the remote volume control 58 to the screen grid tubes through conductors I5- providing volume control at the remote point.

To-tune the receiver from the remote point,

pressure on any of the buttons 56, for instance a switch I30, completes the circuit just traced for local switch I00 with the addition of conductors I3I, I32 and I24. The operation of the circuit is also the same as when button I00 was operated at the local point with the exception that lamp 51 now lights to show that the receiver is being tuned from the remote point. This lamp may be a green color, for instance, to distinguish it from the lamp 59, which may be red. Indicating lamp 3'! at the local point which may be green is also energized when the receiver is being tuned.

With the switch I35 in the common return lead of the holding relays 26, closed, the buttons 25 and do not require constant pressure until the tuning system has rotated to the preselected position. Only contact is necessary to energize the relays 28 which maintain the circuit. However, if it is desired to tune in intermediate stations, the switch I35 may be opened thereby a.llowing the operators to operate the extreme tuning buttons to rotate the tuning elements whereever desired.

Parallel connected remote units may be employed with this system by connecting a duplicate unit E to the leads shown in the dotted lines 63. These may be placed in various rooms of a home or more than one in a room.

Thepresent invention has been shown embodied in one particular form and circuit but it is to be understood that it is adaptable to equivalent systems and is to be limited only by the scope of the appended claims.

What is claimed is:

1. In combination with a radio receiver set having a tuning element and a loudspeaker unit, an electric driving motor having a plurality of selectively operable control circuits, an energizing circuit for the motor, a clutch, a relay in said energizing circuit responsive to the closure thereof for operating the clutch to connect the tuning element to the motor whenever any of said control circuits is rendered operable, means controlled over each of said control circuits and acting upon operation to energize said motor and move it a predetermined distance, means for predetermining said distance and for making it different for each of said control circuits, and means rendered effective by operation of said relay to by-pass the loudspeaker unit whereby silent tuning of the receiver may be positively effected.

2. In combination with a radio receiver set having a tuning element and a loudspeaker unit, an 5 electric driving motor having a plurality of selectively operable control circuits, means controlled over each circuit and acting upon operation to energize said motor to move it a predetermined distance, means rendered effective by said motor upon movement of said predetermined distance for opening the motor circuit, means for predetermining said distance and for making it difierent for each of said control circuits, means effective upon movement of said motor to by-pass the loudspeaker unit whereby silent tuning of said receiver may be operatively efiected, and means rendered effective by the opening of said motor circuit to disconnect the bypass of said loudspeaker whereby operation of said set at its new position of tuning may be resumed.

LEWIS M. CLEIVZENT. 

